Electric heater



Dec. 23, 1952 H. w. SUI-IR 2,623,154

ELECTRIC HEATER Filed Feb. 25, 1950 2 SHEETS-SHEET 1 Fae.

INVENTOR.

mm w. M

Ar'ronuav Deb. 23, 1952 H. w. UHR 2.62:3,154

ELECTRIC HEATER Filed Feb. 25, 1950 2 SHEETS-SHEET 2 28 H IIIWIIIIIM! Ml B m 24 m 24 m INVENTOR.

Arronuev Patented Dec. 23, 1952 UNITED STATES PATENT OFFICE 2,623,154 I p I.

ELECTRIC HEATER Herman W. Suhr, Milwaukee, Wis., assignor to Acme .Sheet Metal Works, Milwaukee, Wis., a corporation of Wisconsin Application February 25, 1950, Serial No. 146,184

The invention relates to heaters and more particularly to electric heaters.

In some forms of electric heaters the electrically heated element or elements are disposed in an open position to be blown on byair fromv a fan.v Heaters of the types above described are only used for. heating a limited area about the heater,- and they are not efiicient as the air blown on the heating element by the fan hasthe effect of darkening the incandescent element so thatit does not operate at its highest efiiciency. Theobject of the presentinvention is to provide aheater of high efficiency in which the heating elements will operate continuously at an incandescent or glowing heat andv in which this heat is-efliciently distributed to the air. particularly, according tothe invention, the heatingelement is mounted in a conduit through which air to be heated is passed at a relatively.

slow rate or velocity and a much larger body of air is passed about theexterior Wall of the conduit at a relatively high rate or velocity past More " it Claims. (o1. 219 s9 signed to be mounted in a conduit 6 through which air is drawn by a suctionfan I drivenby a belt connection 8 with an electric motor 9, the heater having side bracket portions I0 secured to the side walls of the conduit 6 to support the heater therein. I

The heater structure is formed of a number of sheet metal plates which are secured together by sets of spaced tie bolts II to provide one or more inner conduits I2 and an outer surrounding conduit l3. I

These conduits I2 and I3 are formed by sheet metal members I4, I5, and I6.

The members I4 have longitudinally corrugated portions I! and bumps or projections I8 forming stops, and they also have lengthwise extending corrugated end portions IS.

The members IE on one side of each conduit I2 are formed to provide a side wall 20 for this conduit and are then bent backwardly at 2| and outwardly at 22 from each-end of said wall radiating fins forming integral parts of the conduit enclosing the heater, said heater being mounted in'an air circulating duct by which the heated air may be distributed. to any desired place. The heater of this invention is made up of a number of units which number may be varied to suit the heating requirements, and it may be used for house heating in place of the usual furnaces. I v

A further object ofthe invention is to provide a, heating apparatus comprising an inner conduit and outer conduit through which air is circu lated, the air being circulated through the innerconduit at a rate tomaintain incandescence of the electrical heated element disposed therein.

The invention consists in the several features hereinafter set forth and. more particularly de fined by claims at the conclusion hereof.

In. the drawingsf. a Fig. 1 is an end elevation view of a heater embodying the invention; r

Fig. 2 is a side elevation view of the heater; Fig. 3 is a detailed sectional .view taken on the line 3--3 ofFigs 5; I

Fig. 4 isa top plan view of the heater;

Fig. 5, is a view of the heater installed ina circulatory heating systenn I Referring tothe drawings, the heater is de- 20, the parts 22 being lengthwise corrugated.

The members I6 are generally similar to the members I5, but since they have the heating element terminals secured thereto, they are formed to provide a side wall 23 for the other side of each conduit I2 and are then bent backwardly at 24, so that at their upper and lower ends 25 they overlap and intermediate their ends they are bent outwardly at 25 and formed with lengthwise extending corrugations.

I The projections I8 form stops against which the side walls 20 and 23 of the members I5 and I6 abut in the assembled position of the units.

End plates 21 of heavier sheet metal have the bracket portions I0 previously referred to and sets of spaced apertured ears 28 through which the tie bolts II pass. All the members I4, I5, and I6 have apertures therein alined with the apertures in the ears 28, and after these parts areassembled on bolts II, they are clamped in assembled position by nuts 29 on the threaded ends of said bolts. The plates 21 also have a longitu dinally extending .U-shaped rib portion 36.1

A cover 3| is mounted over the tops or air entrance side of the'conduits I2 and is provided with openings 32 which provide a considerably restricted opening to said conduits. It will be (see. Figs. 1, 2, and 4) are not more than one-third of the area of the inner conduit. As shown, the centers of these openings are alined with the walls l4 separating the conduits. These restricted inlets have the effect of reducing the velocity or rate of flow of the air flowing through the conduits l2.

Terminal connections are mounted at opposite ends of the conduits 12. Each connection comprises a threaded rod 33 extending through apertures formed in the wall 23 and the overlapped parts 24 of the members l6. Each rod is insulated from the member It by insulating washers 34 and 35. At their outer ends each rod carries a metal washer 36 clamped against the washer by a nut 31, and an apertured buss bar 38 is clamped to the rod between the nut 31 and a nut 39. The buss bar 38 connects all the terminals at one end of the unit together and is connected to any suitable supply of electric current. The inner end of each rod 33 has a nut 40 in clamping engagement with the washer 34, an apertured angle arm 4!, a metal washer 42, and

a nut 43 clamping these parts together and also clamping the end of the high resistance Wire 44 forming the heating element between said nut 43 and the washer 42. The heating element has the wire 44 wound on a tubular core 45 of ceramic insulating material which is connected to the arms 4| at opposite ends of the conduit by tie wires 46 passing through apertures in said core and said arms. The heating element may be of any suitable type and need not necessarily be of wire but may be made of any suitable resistance material which will glow under the heating. effectv of the electric current. For example, this element may be of the type which goes by the trade name Calrod.

The heater above described is mounted in the conduit 6 as previously noted, and preferably asbestos paper 41 or other heat insulating material is disposed between those portions of the walls of conduit 6 and the adjacent sides of the unit.

The corrugations exterior of the conduit [2 provide a more extensive heat radiating surface than straight or plain fins, and they also due to their sinuous form serve to create resistance and friction to the air. passing between them.

- The parts [4, l5, and I5 may be formed from thin sheet metal stock of copper, aluminum, or magnesium.

With the above construction when electric current is supplied to the buss bars 38, the heating elements are heated to an incandescent or glowing temperature, and as the air is drawn in through the inlet conduit 41 of one form of heater shown in Fig. 5 by the suction fan 1, it passes down through this conduit and through the heater structure above described, the air passing through theconduits I2 moving at a slower rate than that passing through the surrounding conduit 13 containing the radiating fins above described. While in any electric heater all the current furnished is dissipated in the form of heat in prior systems using a forced air supply the heating elements do not operate at full glowing temperature, so that theair passing by them is not as highly heated as in the present structure. Furthermore, the present invention makes it possible to efficiently heat a large volume of air which may be directed to any room or rooms to be heated. In Fig. 5 the heated air is exhausted by the fan 1 into a header 48 which may have .an adjustable damper 49 disposed therein.

Itwill be noted that cover 3| has a fiance 5% that engages over one side of the inner conduits and that the other side 5| of the cover extends down on the other side of the conduits and at the lower edge of this side is provided with tubular portions 52 to receive angled locking pins 53 which may be pushed lengthwise of said guides so that their front ends engage in apertures 54 in the end plates 21 to lock the cover in position. f

In the form shown, only two of the sides of limited to any specific form except as such limitations' are includedin the claims.

What I claim as my invention is:

1. In a heating apparatus, the combination of a conduit through which air is circulated, a heater disposed in said conduit and forming therewith a plurality of inner conduits and an outer conduit, an electrically heated element mounted in each of said inner conduits, heat radiating sinuously curved lengthwise extending sheet metal fins disposed in said outer conduit and extending substantially across the same and forming parts of the Walls of said inner conduits, and an inlet opening not exceeding one-third of the area of each inner conduit restricting the flow of air through said inner conduit to maintain the operation of said electrically heated element at a glowing temperature.

2. In aheating apparatus, a heater for mounting in an enclosing conduit comprising a plurality of sheet metal members forming inner conduits with a common wall between said conduits, each of said members having a heat radiating fin projecting from the wall of said inner conduit and extending to the inner wall of the enclosing conduit, an electrically heated element members and brackets together as a unit.

3. In aheating apparatus, a heater for mount- I ing in an enclosing conduit comprising a plurality of sheet metal plates forming inner conduits of generally polygonal cross section, one

of said plates forming a common dividing wall between adjacent conduits, the plates forming the ends and the dividing walls between said inner conduits each having an integral heat radiating fin projecting from'the wall of said inner conduit into proximity with the wall of the en closing conduit, the plates forming the sides of said inner conduit having an integral flange portion projecting as a heatradiating fin from said inner conduit and into proximity with thewall of the enclosing conduit and disposed between the fins of said first named plates, an electrically heated element mounted within each inner conduit in spaced relation to the sides thereof, means securing said plates in assembled relation, and means at the entrance end ofsaid inner conduits restricting the flow of air therethrough.

4. In a heating apparatus, a heater for mounting in an enclosing conduit comprising a plurality of sheet metal plates forming inner conduits of generally polygonal cross section, one of said plates forming a common dividing wall between adjacent conduits, the plates forming the ends and dividing Walls between said inner conduits each having an integral heat radiating fin projecting from the wall of said inner conduit into proximity with the wall of the enclosing conduit, the plates forming the sides of 5 said inner conduit having spaced integral flange portions projecting as heat radiating fins from said inner conduit and into proximity with the wall of the enclosing conduit and disposed between the fins of said first named plates, an electrically heated element mounted within each inner conduit in spaced relation to the side thereof, means for securing said plates in assembled relation, and means at the entrance end of said inner conduits restricting the flow of air therethrough.

HERMAN W. SUHR.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,701,096 Bowling et a1. Feb. 5, 1929 1,705,812 Fisher Mar. 19, 1929 1,754,232 Fisher Apr. 15, 1930 1,902,074 Holinger Mar. 21, 1933 2,119,161 Hay M May 31, 1938 2,353,247 Kuettel July 11, 1944 2,405,072 Trilling et a1. July 30, 1946 2,405,783 Gardenhour Aug. 13, 1946 2,443,983 Gustaison et a1. June 22, 19% 2,486,501 Solocs ct ai. Nov. 1, 1949 

